Pong

Pong (marketed as PONG) is one of the earliest arcade video games, and is a tennis sports game featuring simple two-dimensional graphics. The aim is to defeat an opponent, either computer-controlled or a second player, by earning a higher score. The game was originally manufactured by Atari Incorporated (Atari), who released it in 1972. Pong was created by Allan Alcorn as a training exercise assigned to him by Atari founder Nolan Bushnell. Bushnell based the idea on an electronic ping-pong game included in the Magnavox Odyssey, which later resulted in a lawsuit against Atari. Surprised by the quality of Alcorn's work, Atari decided to manufacture the game.

Source: Wikipedia, "Pong," available under the CC-BY-SA License.